Solid-state battery, positive electrode active material, and electric device

Abstract

The present application provides a solid-state battery, a positive electrode active material, and an electric device. The solid-state battery comprises a positive electrode material, and the positive electrode material comprises a positive electrode active material, a first electrolyte layer coated on a surface of the positive electrode active material, and a second electrolyte layer coated on a surface of the first electrolyte layer; the material of the first electrolyte layer comprises a compound having a general formula of Li1+x1+2z1Ay1Bz1Sa1Cl6-2a1-b1Fb1; and the material of the second electrolyte layer comprises a first sulfide electrolyte. The solid-state battery has a good cycling performance and rate performance.

Description

Solid-state batteries, positive electrode active materials, and electrical devices

[0001] Related applications

[0002] This application claims priority to Chinese patent application No. 2024119974659, filed on December 31, 2024, entitled "Solid-state battery, positive electrode active material and electrical device", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of secondary battery technology, and more particularly to a solid-state battery, a positive electrode active material, and an electrical device. Background Technology

[0004] Solid-state batteries use a non-flammable solid electrolyte instead of the organic electrolyte in traditional liquid secondary batteries, significantly improving battery safety and considered the next generation of batteries closest to industrialization. Solid-state batteries also attract considerable attention due to their superior energy density. However, the cycle performance and rate performance of all-solid-state batteries currently require further improvement. Summary of the Invention

[0005] To achieve the above objectives, this application provides a solid-state battery, a positive electrode active material, and an electrical device with good cycle performance and rate performance.

[0006] A first aspect of this application provides a solid-state battery, including a positive electrode material, the positive electrode material including a positive electrode active material, a first electrolyte layer coated on the surface of the positive electrode active material, and a second electrolyte layer coated on the surface of the first electrolyte layer;

[0007] The material of the first electrolyte layer includes Li 1+x1+2z1 A y1 B z1 S a1 Cl 6-2a1-b1 F b1 The compound has the following properties: 0 < a1 ≤ 0.5, 0.05 ≤ b1 ≤ 0.2, 0 ≤ y1 ≤ 1, 0 ≤ z1 ≤ 1, where A and B are heterovalent metal elements, y1 and z1 are not simultaneously 0, the oxidation state of A is V1, the oxidation state of B is V2, x1 = 5 - 2z1 - V1*y1 - V2*z1, 0 ≤ x1 ≤ 1;

[0008] The material of the second electrolyte layer includes the first sulfide electrolyte.

[0009] In the aforementioned solid-state battery, a compound having the above-mentioned general formula is disposed as a first electrolyte layer between the second electrolyte layer of the sulfide electrolyte and the positive electrode active material. This enables the positive electrode material to have a stable structure and high ionic conductivity, thereby improving the cycle performance and rate performance of the solid-state battery.

[0010] In some embodiments, 0.25 ≤ a1 ≤ 0.5. Reasonably controlling the value of a1, i.e., controlling the proportion of S element in the compound, is beneficial to further improve the ionic conductivity of the compound itself, thereby improving the rate performance of the solid-state battery, and simultaneously enhancing or improving the stability of the sulfide-halide interface.

[0011] In some embodiments, 0.05 ≤ b1 ≤ 0.1. Controlling the value of b1, i.e., controlling the proportion of F element in the compound, can further reduce the interfacial impedance between the compound and the sulfide electrolyte, thereby improving the cycle performance and rate performance of the solid-state battery.

[0012] In some embodiments, 1 ≤ V1 - V2 ≤ 2. A and B are heterovalent metal elements, and the difference in their oxidation states must be controlled to be 1 or 2. This ensures that A and B have relatively close ionic radii, which is beneficial for the preparation of the compound and the stability of its structure.

[0013] In addition, by using appropriate A and B elements, the interfacial impedance between the compound and the sulfide electrolyte can be further reduced, thereby improving the cycle performance and rate performance of solid-state batteries.

[0014] In some embodiments, A includes one or more of the elements Ta, Nb, V, Ti, Zr, and Hf; optionally, A includes one or more of the elements Ta and Nb.

[0015] In some embodiments, z1 is 0 or B includes one or more of the elements Zr, Hf, Y, Sc, La, Ce, Eu, Gd, Er, Yb, Ho, In, Al, Fe, Cu, and Sn; optionally, B includes the absence of Zr or Zr.

[0016] In some embodiments, the material of the first electrolyte layer includes LiTaS. 0.5 Cl 4.95 F 0.05 Li 1.5 Ta 0.5 Zr 0.5 S 0.5 Cl 4.95 F 0.05 Li 1.5 Ta 0.5 Zr0.5 S 0.25 Cl 5.45 F 0.05 Li 2.2 Zr 0.8 Y 0.2 S 0.5 Cl 4.95 F 0.05 Li 1.5 Ta 0.5 Zr 0.5 S 0.5 Cl 4.9 F 0.1 Li 1.5 Ta 0.5 Zr 0.5 S 0.5 Cl 4.8 F 0.2 Li 1.2 Ta 0.8 Zr 0.2 S 0.25 Cl 5.45 F 0.05 Li 1.8 Ta 0.2 Zr 0.8 S 0.25 Cl 5.45 F 0.05 Li 1.8 Ta 0.2 Zr 0.8 S 0.5 Cl 4.95 F 0.05 Li 1.9 Ta 0.1 Zr 0.9 S 0.25 Cl 5.45 F 0.05 Li 1.5 Nb 0.5 Zr 0.5 S 0.25 Cl 5.45 F 0.05 Li 2.8 Zr 0.8 Y 0.2 S 0.5 Cl 4.95 F 0.05 Li 2.5 Zr 0.5 Y 0.5 S 0.25 Cl 5.45 F 0.05 Li 2.5 Zr 0.5 Yb 0.5 S 0.25Cl 5.45 F 0.05 and Li 2.5 Zr 0.8 Er 0.2 S 0.25 Cl 5.45 F 0.05 One or more of them.

[0017] In some embodiments, the first sulfide electrolyte has the following general formula:

[0018] Li x2 PS y2 Cl z2 F a2 , 0<x2<7, 0<y2≤5.5, 0≤z2≤2, 0≤a2<0.2;

[0019] Alternatively, 0 < z2 ≤ 2.

[0020] By using a suitable first sulfide electrolyte, it is possible to better match the materials of the first electrolyte layer, obtain better ionic conductivity and structural stability, and thus improve the rate performance and cycle performance of solid-state batteries.

[0021] In some embodiments, the first sulfide electrolyte includes Li6PS5Cl and Li6PS5Cl. 0.85 F 0.15 Li 5.5 PS 4.5 Cl 1.5 Li 5.7 PS 4.7 Cl 1.3 Li 6.2 PS 5.2 Cl 0.8 Li 6.4 PS 5.4 Cl 0.6 Li 5.5 PS 4.5 Cl 1.45 F 0.05 Li 5.5 PS 4.5 Cl 1.35 F 0.15 and Li 5.7 PS 4.7 Cl 1.25 F 0.05 One or more of them.

[0022] In addition, by properly controlling the thickness of the first electrolyte layer and the second electrolyte, the capacity of the positive electrode active material can be better utilized, while also having good ionic conductivity and structural stability, thereby improving the rate performance and cycle performance of the solid-state battery.

[0023] In some embodiments, the positive electrode active material has one or more of the following characteristics:

[0024] (1) The thickness of the first electrolyte layer is 10 nm to 80 nm;

[0025] (2) The thickness of the second electrolyte layer is 20 nm to 120 nm;

[0026] (3) The Dv50 of the positive electrode material is 3μm to 5μm;

[0027] (4) The positive electrode active material is a single crystal material.

[0028] In some embodiments, the solid-state battery includes a positive electrode, a solid electrolyte layer, and a negative electrode.

[0029] The positive electrode sheet includes a positive active layer, and the positive active layer includes the positive electrode material;

[0030] The solid electrolyte layer includes a second sulfide electrolyte.

[0031] A second aspect of this application provides a positive electrode material, comprising a positive electrode active material, a first electrolyte layer coated on the surface of the positive electrode active material, and a second electrolyte layer coated on the surface of the first electrolyte layer;

[0032] The material of the first electrolyte layer includes Li 1+x1+2z1 A y1 B z1 S a1 Cl 6-2a1-b1 F b1 The compound has the following properties: 0 < a1 ≤ 0.5, 0.05 ≤ b1 ≤ 0.2, 0 ≤ y1 ≤ 1, 0 ≤ z1 ≤ 1, where A and B are heterovalent metal elements, y1 and z1 are not simultaneously 0, the oxidation state of A is V1, the oxidation state of B is V2, x1 = 5 - 2z1 - V1*y1 - V2*z1, 0 ≤ x1 ≤ 1;

[0033] The material of the second electrolyte layer includes the first sulfide electrolyte.

[0034] In some embodiments, the cathode material is the cathode material described in the first aspect.

[0035] A third aspect of this application provides an electrical device comprising the solid-state battery described in the first aspect or the positive electrode material described in the second aspect. Attached Figure Description

[0036] To better describe and illustrate the embodiments or examples provided in this application, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described embodiments or examples, or the best mode of conduct of these applications as currently understood. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0037] Figure 1 is a schematic diagram of the structure of the cathode material according to an embodiment of this application.

[0038] Figure 2 is a schematic diagram of a solid-state battery cell according to an embodiment of this application.

[0039] Figure 3 is an exploded view of a solid-state battery cell according to an embodiment of this application, as shown in Figure 2.

[0040] Figure 4 is a schematic diagram of a battery device according to an embodiment of this application.

[0041] Figure 5 is a schematic diagram of a battery pack according to one embodiment of this application.

[0042] Figure 6 is an exploded view of the battery pack of one embodiment of this application shown in Figure 5.

[0043] Figure 7 is a schematic diagram of an electrical device using a solid-state battery as a power source according to an embodiment of this application.

[0044] Figure 8 shows the material Li of the first electrolyte layer in one embodiment of this application. 1.5 Ta 0.5 Zr 0.5 S 0.5 Cl 4.95 F 0.05 XRD pattern.

[0045] Figure 9 shows the material Li of the first electrolyte layer in one embodiment of this application. 1.8 Zr 0.9 Y 0.2 S 0.5 Cl 4.95 F 0.05 XRD pattern.

[0046] Explanation of reference numerals in the attached drawings: 100, positive electrode active material; 200, first electrolyte layer; 300, second electrolyte layer; 1, battery pack; 2, upper casing; 3, lower casing; 4, battery assembly; 5, solid-state battery cell; 51, casing; 52, solid-state battery cell; 53, cover plate; 6, power-consuming device. Detailed Implementation

[0047] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0049] The "range" disclosed in this application can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. Ranges defined in this way can include or exclude endpoints. Any endpoint can be included or excluded independently, and they can be combined arbitrarily; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60–120 and 80–110 are listed for a specific parameter, it is expected that ranges of 60–110 and 80–120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are also listed, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this application, unless otherwise stated, the numerical range "a–b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0" and "5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥ 2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, when a parameter is described as an integer selected from "2-10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0050] In this application, the terms "multiple" or "various" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0051] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0052] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. The term "implementation" as used herein has a similar understanding.

[0053] Those skilled in the art will understand that the order in which the steps are written in the methods of various embodiments or examples does not imply a strict execution order and does not constitute any limitation on the implementation process. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0054] In this application, unless otherwise specified, A (e.g., B) means that B is a non-limiting example of A, and it is understood that A is not limited to B.

[0055] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0056] Solid electrolytes are the core of all-solid-state batteries, and their performance has a significant impact on the entire battery. Among all current solid electrolyte systems, sulfide solid electrolytes have been widely studied due to their extremely high room-temperature conductivity (1 millisiemens / cm (mS / cm) ~ 10 mS / cm) and excellent mechanical properties. However, the cycle and rate performance of all-solid-state batteries using sulfide solid electrolyte systems are still far lower than those of liquid batteries using traditional organic electrolyte systems.

[0057] Studies have found that there are significant interfacial problems between sulfide solid electrolytes and positive electrode active materials. Sulfides react violently and decompose easily upon contact with the positive electrode active material, thus severely impacting the cycle performance and rate performance of all-solid-state batteries using sulfide solid electrolyte systems.

[0058] Compared to sulfides, halides exhibit good stability at high oxidation potentials, but their conductivity is lower. Furthermore, studies have found that traditional halide electrolytes such as Li3InCl6 or novel high-ionic-conductivity halide systems like LiTaOCl4 are unstable with sulfides, spontaneously reacting to form metal sulfides, further deteriorating the overall ionic conductivity of the electrolyte within the battery cell.

[0059] Based on this, one embodiment of this application provides a solid-state battery, including a positive electrode material, the positive electrode material including a positive electrode active material, a first electrolyte layer coated on the surface of the positive electrode active material, and a second electrolyte layer coated on the surface of the first electrolyte layer;

[0060] The material of the first electrolyte layer includes Li 1+x1+2z1 A y1 B z1 S a1 Cl 6-2a1-b1 F b1 The compound has the following properties: 0 < a1 ≤ 0.5, 0.05 ≤ b1 ≤ 0.2, 0 ≤ y1 ≤ 1, 0 ≤ z1 ≤ 1, where A and B are heterovalent metal elements, y1 and z1 are not simultaneously 0, the oxidation state of A is V1, the oxidation state of B is V2, x1 = 5 - 2z1 - V1*y1 - V2*z1, 0 ≤ x1 ≤ 1;

[0061] The material of the second electrolyte layer includes the first sulfide electrolyte.

[0062] In the aforementioned solid-state battery, a compound having the above-described general formula is disposed as a first electrolyte layer between the second electrolyte layer of the sulfide electrolyte and the positive electrode active material. The presence of this first electrolyte layer reduces direct contact between the sulfide electrolyte and the positive electrode active material, thereby reducing side reactions. Furthermore, the presence of the fluorine (F) element in this compound allows for the formation of a fluoride layer between the sulfide electrolyte and the first electrolyte layer, reducing interfacial element diffusion and effectively lowering interfacial impedance. Simultaneously, the introduction of sulfur (S) element enhances the ionic conductivity of the compound itself. Adding a second sulfide electrolyte to the first electrolyte layer further improves the battery's cycle stability without affecting the ion pathway. Thus, the positive electrode material exhibits a stable structure and high ionic conductivity, improving the cycle performance and rate performance of the solid-state battery.

[0063] Understandably, as mentioned above, "covering a surface" means at least partially covering, that is, it can be partially covered or completely covered.

[0064] Understandably, "A and B are heterovalent metal elements" means that elements A and B have different valence states, and elements A and B can be of the same or different types.

[0065] Without limitation, the chemical formula of the material of the first electrolyte layer can be obtained by methods such as X-ray diffraction (XRD) or energy-dispersive X-ray spectroscopy (EDS).

[0066] Without limitation, the structure of the positive electrode material is shown in Figure 1, including a positive electrode active material 100, and a first electrolyte layer 200 and a second electrolyte layer 300 sequentially coated on the surface of the positive electrode material 100.

[0067] Without limitation, the positive electrode active material is positive electrode active material particles.

[0068] Specifically, the value of a1 includes, but is not limited to: 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, or any two of the aforementioned values. Further, 0.25 ≤ a1 ≤ 0.5. Reasonably controlling the value of a1, i.e., controlling the proportion of sulfur in the compound, is beneficial to further improving the ionic conductivity of the compound itself, thereby improving the rate performance of solid-state batteries, and simultaneously enhancing or improving the stability of the sulfide-halide interface.

[0069] Specifically, the value of b1 includes, but is not limited to: 0.05, 0.08, 0.1, 0.12, 0.15, 0.2, or any two of the aforementioned values. Further, 0.05 ≤ b1 ≤ 0.1. Reasonably controlling the value of b1, i.e., controlling the proportion of F element in the compound, can further reduce the interfacial impedance between the compound and the sulfide electrolyte, thereby improving the cycle performance and rate performance of the solid-state battery.

[0070] In addition, without limitation, the value of y1 includes, but is not limited to: 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, or any two of the foregoing.

[0071] The value of z1 includes, but is not limited to: 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, or any two of the above.

[0072] In some embodiments, 1 ≤ V1 - V2 ≤ 2. A and B are heterovalent metal elements, and the difference in their oxidation states must be controlled to be 1 or 2. This ensures that A and B have relatively close ionic radii, which is beneficial for the preparation of the compound and the stability of its structure.

[0073] In addition, by using appropriate A and B elements, the interfacial impedance between the compound and the sulfide electrolyte can be further reduced, thereby improving the cycle performance and rate performance of solid-state batteries.

[0074] In some embodiments, A includes one or more of the elements Ta, Nb, V, Ti, Zr, and Hf. Further, A includes one or more of the elements Ta and Nb.

[0075] In some embodiments, z1 is 0 or B includes one or more of the elements Zr, Hf, Y, Sc, La, Ce, Eu, Gd, Er, Yb, Ho, In, Al, Fe, Cu, and Sn. Further, B includes the absence of Zr or the Zr element.

[0076] As an example, the material of the first electrolyte layer includes LiTaS. 0.5 Cl 4.95 F 0.05 Li 1.5 Ta 0.5 Zr 0.5 S 0.5 Cl 4.95 F 0.05 Li 1.5 Ta 0.5 Zr 0.5 S 0.25 Cl 5.45 F 0.05 Li 2.2 Zr 0.8 Y 0.2 S 0.5 Cl 4.95 F 0.05 Li 1.5 Ta 0.5 Zr 0.5 S 0.5 Cl 4.9 F 0.1 Li 1.5 Ta 0.5 Zr 0.5 S 0.5 Cl 4.8 F 0.2 Li 1.2 Ta 0.8 Zr0.2 S 0.25 Cl 5.45 F 0.05 Li 1.8 Ta 0.2 Zr 0.8 S 0.25 Cl 5.45 F 0.05 Li 1.8 Ta 0.2 Zr 0.8 S 0.5 Cl 4.95 F 0.05 Li 1.9 Ta 0.1 Zr 0.9 S 0.25 Cl 5.45 F 0.05 Li 1.5 Nb 0.5 Zr 0.5 S 0.25 Cl 5.45 F 0.05 Li 2.8 Zr 0.8 Y 0.2 S 0.5 Cl 4.95 F 0.05 Li 2.5 Zr 0.5 Y 0.5 S 0.25 Cl 5.45 F 0.05 Li 2.5 Zr 0.5 Yb 0.5 S 0.25 Cl 5.45 F 0.05 and Li 2.5 Zr 0.8 Er 0.2 S 0.25 Cl 5.45 F 0.05 One or more of them.

[0077] In some embodiments, the first sulfide electrolyte has the following general formula:

[0078] Li x2 PS y2 Cl z2 F a2 , 0<x2<7, 0<y2≤5.5, 0≤z2≤2, 0≤a2<0.2.

[0079] By employing a suitable first sulfide electrolyte, better compatibility with the materials of the first electrolyte layer can be achieved, resulting in better ionic conductivity and structural stability, thereby improving the rate performance and cycle performance of the solid-state battery. Further, 0 < z² ≤ 2. Without limitation, the first sulfide electrolyte includes Li₆PS₅Cl and Li₆PS₅Cl₂. 0.85 F 0.15 Li 5.5 PS 4.5 Cl 1.5 Li 5.7 PS 4.7 Cl 1.3 Li 6.2 PS 5.2 Cl 0.8 Li 6.4 PS 5.4 Cl 0.6 Li 5.5 PS 4.5 Cl 1.45 F 0.05 Li 5.5 PS 4.5 Cl 1.35 F 0.15 and Li 5.7 PS 4.7 Cl 1.25 F 0.05 One or more of them.

[0080] In addition, by properly controlling the thickness of the first electrolyte layer and the second electrolyte, the capacity of the positive electrode active material can be better utilized, while also having good ionic conductivity and structural stability, thereby improving the rate performance and cycle performance of the solid-state battery.

[0081] In some embodiments, the thickness of the first electrolyte layer is 10 nanometers (nm) to 80 nm. Specifically, the thickness of the first electrolyte layer includes, but is not limited to, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, or any two of the foregoing.

[0082] In some embodiments, the thickness of the second electrolyte layer is 20 nm to 120 nm. Specifically, the thickness of the first electrolyte layer includes, but is not limited to, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, or any two of the foregoing.

[0083] Without limitation, the thickness of the first electrolyte layer and the thickness of the second electrolyte layer can be obtained by scanning the positive electrode material with a transmission electron microscope (TEM) or by scanning the cross-section of the electrolyte sheet with a scanning electron microscope (SEM).

[0084] In some embodiments, the Dv50 of the cathode material is 3 micrometers (μm) to 5 μm. Specifically, the Dv50 of the cathode material includes, but is not limited to, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, or any range between the two.

[0085] Without limitation, the Dv50 of the cathode material can be statistically estimated by SEM analysis or analyzed by a laser particle size analyzer.

[0086] In some embodiments, the positive electrode active material is a single-crystal material. Using a single-crystal positive electrode active material results in better structural stability, easier coating, and improved overall stability of the positive electrode material, thus enhancing the cycle performance of the solid-state battery.

[0087] In some embodiments, the positive electrode active material may be a known positive electrode active material for batteries. As a non-limiting example, the positive electrode active material may include one or more of the following materials: lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include, but are not limited to, one or more of lithium cobalt oxides (such as LiCoO2), lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and their modified compounds. Non-limiting examples of lithium-containing phosphates with an olivine structure include, but are not limited to, one or more of lithium iron phosphate, lithium iron phosphate and carbon composites, lithium manganese phosphate, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites. Non-limiting examples of lithium cobalt oxides may include LiCoO2; non-limiting examples of lithium nickel oxides may include LiNiO2; non-limiting examples of lithium manganese oxides may include LiMnO2, LiMn2O4, etc.; non-limiting examples of lithium nickel cobalt manganese oxides may include LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 Examples of lithium nickel cobalt aluminum oxides include LiNi, etc. 0.8 Co 0.15 Al 0.05 O2.

[0088] In some embodiments, the solid-state battery includes a positive electrode, a solid electrolyte layer, and a negative electrode; the positive electrode includes a positive active layer comprising the positive electrode material; the solid electrolyte layer comprises a second sulfide electrolyte. The aforementioned positive electrode material is particularly suitable for solid-state battery systems with sulfide electrolytes, achieving better cycle performance and rate performance.

[0089] Without limitation, the second sulfide electrolyte can be, for example, Li6PS5Cl, Li6PS5Cl 0.85 F 0.15 Li 5.5 PS 4.5 Cl 1.5 Li 5.7 PS 4.7 Cl 1.3 Li 6.2 PS 5.2 Cl 0.8 Li 6.4 PS 5.4 Cl 0.6 Li 5.5 PS 4.5 Cl 1.45 F 0.05 Li 5.5 PS 4.5 Cl 1.35 F 0.15 Li 5.7 PS 4.7 Cl 1.25 F 0.05 One or more of the following.

[0090] In some embodiments, the solid-state battery is an all-solid-state battery.

[0091] Other embodiments of this application also provide a positive electrode material, including a positive electrode active material, a first electrolyte layer coated on the surface of the positive electrode active material, and a second electrolyte layer coated on the surface of the first electrolyte layer;

[0092] The material of the first electrolyte layer includes Li 1+x1+2z1 A y1 B z1 S a1 Cl 6-2a1-b1 F b1 The compound has the following properties: 0 < a1 ≤ 0.5, 0.05 ≤ b1 ≤ 0.2, 0 ≤ y1 ≤ 1, 0 ≤ z1 ≤ 1, where A and B are heterovalent metal elements, y1 and z1 are not simultaneously 0, the oxidation state of A is V1, the oxidation state of B is V2, x1 = 5 - 2z1 - V1*y1 - V2*z1, 0 ≤ x1 ≤ 1;

[0093] The material of the second electrolyte layer includes the first sulfide electrolyte.

[0094] Understandably, the above-mentioned cathode material has the same technical solution and advantages as the cathode material in the solid-state battery described above, and will not be repeated here.

[0095] In some embodiments, the material of the first electrolyte layer in the positive electrode material can be synthesized by a mechanochemical method. Without limitation, the synthesis method includes the following steps:

[0096] The material for the first electrolyte layer is prepared by ball milling a mixture of LiCl, Li2S, LiF, and halides of metals A and B.

[0097] Without limitation, examples of metal halides include: TaCl5, NbCl5, VCl5, ZrCl4, HfCl4, TiCl4; examples of metal halides include: ZrCl4, HfCl4, TiCl4, YCl3, ScCl3, LaCl3, CeCl3, EuCl3, GdCl-3, ErCl3, YbCl3, HoCl3, InCl3, AlCl3, FeCl3, CuCl2, SnCl2.

[0098] Without limitation, the ball mill speed can be 500 rpm to 700 rpm.

[0099] Without limitation, the mass ratio of zirconium beads to the mixture used in the ball mill is (20-50):1.

[0100] Without limitation, the ball milling time can be 6 hours (h) to 180 hours.

[0101] In some embodiments, the method for preparing the cathode material includes the following steps:

[0102] The positive electrode active material is mixed with the material of the first electrolyte layer and then heated to coat the surface of the positive electrode active material with the material of the first electrolyte layer, thus forming the first electrolyte layer.

[0103] A second electrolyte layer is formed by dry-packing a first sulfide electrolyte onto the surface of the first electrolyte layer.

[0104] In some embodiments, the mass ratio of the positive electrode active material to the material of the first electrolyte layer is (70%–99%):(1%–30%).

[0105] Without limitation, the mixing method can be manual mixing in a mortar and pestle or ball milling or roller milling. The speed of ball milling or roller milling can be 200 rpm to 320 rpm, and the time can be 20 min to 70 min.

[0106] Without limitation, the heat treatment temperature is 180°C to 350°C. The heat treatment can be carried out in a vacuum tube furnace or an inert atmosphere muffle furnace.

[0107] Other embodiments of this application also provide an electrical device, including a solid-state battery as described above or a positive electrode material as described above.

[0108] The solid-state battery and power device of this application will be described below with appropriate reference to the accompanying drawings.

[0109] Unless otherwise specified, the term "solid-state battery" as used in this application refers to a battery in which the electrolyte includes a solid electrolyte. Typically, a solid-state battery includes a positive electrode, a solid electrolyte layer, and a negative electrode. During charging and discharging, active ions repeatedly insert and extract between the positive and negative electrodes. The solid electrolyte layer serves to conduct ions between the positive and negative electrodes and also isolates them, thus preventing short circuits. Therefore, solid-state batteries do not require the separator found in traditional lithium-ion batteries.

[0110] In some embodiments, the positive electrode includes a positive current collector and a layer of positive active material disposed on at least one surface of the positive current collector.

[0111] Without limitation, the weight percentage of the positive electrode material in the positive electrode active material layer can be ≥60wt%, and can be selected as 60wt% to 85wt%.

[0112] In some embodiments, the positive electrode active material layer further includes a positive electrode electrolyte material. The positive electrode electrolyte material can enhance the ion conductivity of the positive electrode layer, reduce interfacial impedance, and promote the charge transfer efficiency and full release of the capacity of the positive electrode active material with the external environment. Non-limitingly, the weight percentage of the positive electrode electrolyte material in the positive electrode active material layer can be from 13 wt% to 38 wt%. In some embodiments, the positive electrode electrolyte material is a third sulfide electrolyte; for example, it can be one or more of LiPSC, LiGePS4, and LiPS.

[0113] In some embodiments, the positive electrode active material layer further includes a conductive agent (which may be referred to as a positive electrode conductive agent). As a non-limiting example, the positive electrode conductive agent may be a carbon conductive agent. Non-limitingly, the carbon conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the positive electrode conductive agent may include, but is not limited to, one or more of SP, KS-6, acetylene black, branched Ketjen black ECP, SFG-6, vapor-grown carbon fiber VGCF, carbon nanotubes (CNTs), and graphene. Non-limitingly, the weight percentage of the positive electrode conductive agent in the positive electrode active material layer may be 0–10 wt%, more further 0–8 wt%, even further 0–5 wt%, and even further 0.5 wt%–2.5 wt%. When the positive electrode material is prepared into a positive electrode active material layer using a dry method, the positive electrode conductive agent can be incorporated into the positive electrode material, thereby improving the conductivity of the positive electrode active material layer.

[0114] In some embodiments, the mass percentages of the positive electrode material, positive electrode electrolyte material, and conductive agent in the positive electrode active material layer are (60%–85%):(13%–38%):2%.

[0115] In some embodiments, the positive electrode active material layer optionally includes a binder (which may be referred to as a positive electrode binder). As a non-limiting example, the positive electrode binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins. The aforementioned non-limiting examples of positive electrode binders are all organic binders and belong to organic components. Typically, the weight percentage of the positive electrode binder in the positive electrode active material layer can be 0–10 wt%, more commonly 0–8 wt%, even more commonly 0.1 wt%–5 wt%, and even more commonly 2.5 wt%–5 wt%. When the positive electrode material is formulated into a positive electrode slurry using a wet process and then the positive electrode active material layer is prepared, the positive electrode binder can be placed in the positive electrode slurry, which can assist in film formation and also promote the formation of a good electrical contact network between the active particles in the positive electrode active material layer.

[0116] Non-limiting, the positive electrode active material layer may include a positive electrode material, a positive electrode electrolyte material, a positive electrode conductive agent, and a positive electrode binder. The types and contents of each component can be found in the context of this application.

[0117] As a non-limiting example, the positive current collector has two surfaces that are opposite to each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0118] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. In the positive electrode current collector, the composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. In the positive electrode current collector, the composite current collector may be obtained by forming a metal material on the polymer material substrate. Non-limiting examples of the metal material in the positive electrode current collector may include at least one of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. Non-limiting examples of the polymer material substrate in the positive electrode current collector may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0119] In some embodiments, the positive electrode sheet can be prepared by: dry mixing the components used to prepare the positive electrode sheet, then heating and pressurizing the mixed material to knead it into a clump, hot rolling to form a self-supporting positive electrode sheet, and hot rolling to combine the self-supporting positive electrode sheet with a positive current collector. The self-supporting positive electrode sheet can be combined with at least one side (single or double sides) of the positive current collector to obtain the positive electrode sheet. Non-limitingly, a dual planetary mixer can be used for dry mixing. Non-limitingly, a kneading and pressing machine can be used for heating and pressurizing. Non-limitingly, the temperature for hot rolling can be 75°C to 85°C, and further, such as 75°C, 78°C, 80°C, 82°C, 85°C, etc. The method of assembling solid-state batteries using positive electrode sheets is suitable for industrial mass production.

[0120] In some embodiments, the positive electrode sheet can be prepared by dispersing the components used to prepare the positive electrode sheet, such as positive electrode active particles, positive electrode electrolyte particles, positive electrode conductive agent, positive electrode binder, and any other components, in an organic solvent to form a positive electrode slurry. Further, the positive electrode slurry is coated onto at least one surface of the positive electrode current collector, and after drying, cold pressing, and other processes, the positive electrode sheet is obtained. Cold pressing can be performed using a cold rolling mill. Non-limitingly, the organic solvent in the positive electrode slurry can include one or more of p-xylene, trimethylbenzene, butyl butyrate, heptane, etc., and more specifically, p-xylene. The surface of the positive electrode current collector coated with the positive electrode slurry can be a single surface of the positive electrode current collector or both surfaces of the positive electrode current collector. The solid content (mass percentage) of the positive electrode slurry can be 40 wt% to 80 wt%. The viscosity of the positive electrode slurry at room temperature can be adjusted to 5000 mPa·s to 25000 mPa·s. When coating the positive electrode slurry, the coating density per unit area, measured by dry weight (excluding solvent), can be 15 mg / cm², based on the amount coated on one side of the positive electrode current collector. 2 )~35mg / cm 2 However, this is not the only possibility. The compacted density of the positive electrode sheet can be 3.0 g / cm³. 3 ~3.6g / cm 3 3.3g / cm³ is an option. 3 ~3.5g / cm 3 .

[0121] In some embodiments, the negative electrode sheet includes a negative current collector and a negative active material layer disposed on at least one surface of the negative current collector, the negative active material layer including a negative active material.

[0122] Unless otherwise stated, the negative electrode active material layer in this application includes at least a negative electrode active material layer.

[0123] Unless otherwise stated in this application, the negative electrode active material layer includes at least a negative electrode active material.

[0124] Without limitation, the negative electrode active material layer may include a negative electrode electrolyte material.

[0125] In this application, unless otherwise specified, "negative electrode electrolyte material" refers to a solid electrolyte material that can be used in the negative electrode active material layer. The negative electrode electrolyte material can enhance the ion conductivity of the negative electrode active material layer, reduce interfacial impedance, and promote the efficient charge transfer between the negative electrode active material and the external environment, as well as the full release of its capacity.

[0126] In some embodiments, the negative electrode sheet includes a negative electrode active material layer, which includes a negative electrode active material.

[0127] Without limitation, the weight percentage of the negative electrode active material in the negative electrode active material layer can be ≥80wt%, and more preferably ≥90wt%.

[0128] Non-limiting, the weight percentage of the negative electrode electrolyte material in the negative electrode active material layer can be 0 to 30 wt%, preferably 0.1 wt% to 30 wt%, and further preferably 5 wt% to 20 wt%.

[0129] In some implementations, the negative electrode active material is a lithium indium alloy (InLi alloy).

[0130] In some embodiments, the negative electrode active layer or negative electrode sheet is an InLi alloy film.

[0131] In some embodiments, the negative electrode active material may also be a negative electrode active material known in the art for use in solid-state batteries. As a non-limiting example, the negative electrode active material may include one or more of the following materials: elemental silicon, elemental tin, silicon-carbon composites, silicon suboxide, graphite, and metallic lithium. However, this application is not limited to these materials or substances, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0132] In some embodiments, the negative electrode sheet may include a negative current collector and a negative active material layer disposed on at least one surface of the negative current collector, the negative active material layer comprising a negative active substance. As a non-limiting example, the negative current collector has two surfaces opposite to each other in its own thickness direction, and the negative active material layer is disposed on either or both of the two opposite surfaces of the negative current collector.

[0133] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. In the negative electrode current collector, the composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. In the negative electrode current collector, the composite current collector may be formed by forming a metal material on the polymer material substrate. Non-limiting examples of the metal material in the negative electrode current collector may include one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Non-limiting examples of the polymer material substrate in the negative electrode current collector may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0134] In some embodiments, the negative electrode active material layer optionally includes a conductive agent (which may be referred to as a negative electrode conductive agent). Non-limitingly, the negative electrode conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. Non-limitingly, the weight percentage of the negative electrode conductive agent in the negative electrode active material layer may be 0–15 wt%, more preferably 0–10 wt%, and even more preferably 0–5 wt%.

[0135] In some embodiments, the negative electrode active material layer optionally includes a binder (denoted as negative electrode binder). As a non-limiting example, the negative electrode binder may include one or more of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS). Non-limitingly, the weight percentage of the negative electrode binder in the negative electrode active material layer may be 0–10 wt%, more preferably 0–5 wt%, even more preferably 1 wt%–5 wt%, and even more preferably 1 wt%–3 wt%.

[0136] In some embodiments, the negative electrode active material layer may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)). The weight percentage of the other additives in the negative electrode active material layer may be 0–15 wt%, more preferably 0–10 wt%, even more preferably 0–5 wt%, even more preferably 0–3 wt%, and even more preferably 0–2 wt%.

[0137] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as negative electrode active particles, negative electrode conductive agent, negative electrode binder, and any other components, in a solvent (a non-limiting example of a solvent is p-xylene) to form a negative electrode slurry. Further, the negative electrode slurry is coated onto at least one surface of the negative electrode current collector, and after drying, cold pressing, and other processes, the negative electrode sheet is obtained. Cold pressing can be performed using a cold rolling mill. The surface of the negative electrode current collector coated with the negative electrode slurry can be a single surface of the negative electrode current collector or both surfaces of the negative electrode current collector. The solid content of the negative electrode slurry can be 30wt% to 70wt%, optionally 40wt% to 60wt%. The viscosity of the negative electrode slurry at room temperature can be adjusted to 2000 mPa·s to 10000 mPa·s, optionally 3000 mPa·s to 10000 mPa·s. When coating the negative electrode slurry, the coating density per unit area, based on the amount coated on one side of the negative electrode current collector and calculated by dry weight (excluding solvent), can be 1.5 mg / cm³. 2 ~22mg / cm 2 However, this is not the only possibility. The compaction density of the negative electrode sheet can be 1.0 g / cm³. 3 ~2.0g / cm 3 1.0g / cm³ is an optional value. 3 ~1.8g / cm 3 .

[0138] In some embodiments, the solid electrolyte layer can be prepared using a dry method. In some embodiments, the solid electrolyte layer can be formed by pressing a solid electrolyte material into a solid electrolyte membrane. In other embodiments, the solid electrolyte layer is formed by pressing the constituent raw materials of the solid electrolyte layer onto an electrode layer. In still other embodiments, the solid electrolyte membrane can also be prepared using methods such as fibrosis combined with calendering, melt extrusion, or spraying.

[0139] In some embodiments, the thickness of the solid electrolyte layer can be 0.1 μm to 1000 μm, and can be selected as 10 μm to 100 μm, 100 μm to 800 μm, 500 μm to 800 μm, etc.

[0140] In a non-limiting manner, the positive electrode, the solid electrolyte layer, and the negative electrode can be assembled in a stacked manner, with the solid electrolyte layer placed between the positive electrode and the negative electrode.

[0141] Non-limitingly, a solid-state battery cell can be prepared by sequentially stacking a positive electrode, a solid electrolyte membrane, and a negative electrode, with the solid electrolyte membrane placed between the positive and negative electrodes, and then rolling. The rolling process can be either cold rolling or hot rolling. A non-limiting example of a hot rolling temperature is 180°C.

[0142] In some embodiments, the solid-state battery may include an outer packaging. This outer packaging can be used to encapsulate the aforementioned solid-state battery cell.

[0143] In some embodiments, the outer packaging of a solid-state battery can be a rigid shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of a solid-state battery can also be a soft pack, such as a pouch-type soft pack. The material of the soft pack can be plastic; further, non-limiting examples of plastics may include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0144] This application does not impose any particular limitation on the shape of the solid-state battery cell; it can be cylindrical, square, or any other arbitrary shape. For example, Figure 2 shows a square solid-state battery cell 5 as an example.

[0145] In some embodiments, referring to FIG3, the outer packaging may include a housing 51 and a cover plate 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover plate 53 can be placed over the opening to close the receiving cavity. A solid-state battery cell 52 is encapsulated within the receiving cavity. The number of solid-state battery cells 52 contained in the solid-state battery cell 5 may be one or more, which can be selected by those skilled in the art according to actual needs.

[0146] Solid-state batteries can be battery device 4 or battery pack 1.

[0147] The battery device includes at least one solid-state battery cell. The number of solid-state battery cells in the battery device can be one or more, and those skilled in the art can select an appropriate number according to the application and capacity of the battery device.

[0148] Figure 4 shows a battery device 4 as an example. Referring to Figure 4, in the battery device 4, multiple solid-state battery cells 5 can be arranged sequentially along the length of the battery device 4. Of course, they can also be arranged in any other arbitrary manner. Furthermore, the multiple solid-state battery cells 5 can be fixed in place by fasteners.

[0149] Optionally, the battery device 4 may also include a housing with a receiving space in which a plurality of solid-state battery cells 5 are housed.

[0150] In some embodiments, the battery devices described above can also be assembled into a battery pack, and the number of battery devices contained in the battery pack can be one or more. Those skilled in the art can select an appropriate number according to the application and capacity of the battery pack.

[0151] Figures 5 and 6 illustrate a battery pack 1 as an example. Referring to Figures 5 and 6, the battery pack 1 may include a battery compartment and multiple battery devices 4 disposed within the battery compartment. The battery compartment includes an upper compartment 2 and a lower compartment 3, with the upper compartment 2 covering the lower compartment 3 to form a closed space for accommodating the battery devices 4. The multiple battery devices 4 can be arranged in any manner within the battery compartment.

[0152] In a non-limiting sense, solid-state batteries can be used as a power source for electrical devices or as an energy storage unit for electrical devices. Electrical devices can include, but are not limited to, mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc. Mobile devices can be, for example, mobile phones, laptops, etc.; electric vehicles can be, for example, pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, electric motorcycles, power tools, etc., but are not limited to these. This electrical device can also be applied to military equipment, aerospace, and other fields, and can also be applied to energy storage power systems such as hydroelectric, thermal, wind, and solar power plants.

[0153] As an electrical device, solid-state batteries can be selected based on its usage requirements.

[0154] Figure 6 shows an example of an electrical device 6. This electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of this electrical device for solid-state batteries, a battery device or battery pack can be used.

[0155] Another example device could be a mobile phone, tablet, or laptop. These devices typically require a thin and light design and can use solid-state batteries as their power source.

[0156] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the application will be further described in detail below with reference to embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its applications. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0157] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0158] Example 1

[0159] 1) Preparation of cathode materials

[0160] LiCl, Li₂S, LiF, and TaCl₅ are processed according to the general formula LiTaS. 0.5 Cl 4.95 F 0.05 The ingredients were mixed and ball-milled at 650 rpm for 100 hours. The mass ratio of zirconium beads used in the ball mill to the mixed materials was 45:1. The material used to prepare the first electrolyte layer was LiTaS. 0.5 Cl 4.95 F 0.05 ;

[0161] Single-crystal LiNi, the positive electrode active material 0.8 Co 0.1 Mn 0.1 O2 and the material of the first electrolyte layer were rolled at a mass ratio of 80%:20% at a speed of 150 rpm for 50 min; then heated in a vacuum tube furnace at a temperature of 200℃ to prepare the first electrolyte layer with a thickness of 50 nm.

[0162] The material obtained by heat treatment is mixed with the sulfide electrolyte Li6PS5Cl 0.85 F 0.15 Dry coating was performed by secondary coating at a mass ratio of 95%:5% using high-energy ball milling at 250 rpm for 40 min. The mass ratio of grinding beads (zirconia beads) to the material was 10:1 to prepare the second electrolyte layer with a thickness of 80 nm. The resulting cathode material had a Dv50 of 5 μm.

[0163] 2) Preparation of positive electrode sheet

[0164] The positive electrode material prepared in step 1) is combined with the sulfide electrolyte Li 5.7 PS 4.7 Cl 1.3 Conductive carbon is mixed in a weight ratio of 80%:18%:2% to obtain the spare material for the positive electrode sheet.

[0165] 3) Negative electrode plate

[0166] Li-In alloy foil with a thickness of 0.3 mm was selected.

[0167] 4) Electrolyte membrane

[0168] The selected electrolyte is a sulfide solid electrolyte, Li6PS5Cl.

[0169] 5) Battery manufacturing

[0170] First, add about 100mg of LPSC to the mold and compact the sulfide solid electrolyte powder with a pressure of 125MPa to form an electrolyte membrane. Then, add 15mg of spare material for the positive electrode sheet and Li-In alloy foil to both sides of the electrolyte membrane as the positive and negative electrodes, respectively. Press the mold battery with a pressure of 500MPa and hold the battery under pressure for 5 minutes to prepare a solid-state battery.

[0171] The preparation method of the solid-state battery in Example 2 is the same as that in Example 1, the main difference being that in step 1), LiCl, Li2S, LiF, TaCl5, and ZrCl4 are prepared according to the general formula Li 1.5 Ta 0.5 Zr 0.5 S 0.5 Cl 4.95 F 0.05 The ingredients were mixed and ball-milled to prepare the first electrolyte layer material, Li. 1.5 Ta 0.5 Zr 0.5 S 0.5 Cl 4.95 F 0.05 The material of the first electrolyte layer is Li. 1.5 Ta 0.5 Zr 0.5 S 0.5 Cl 4.95 F 0.05 The XRD pattern is shown in Figure 8.

[0172] The solid-state battery in Example 3 is prepared in the same way as in Example 1, except that in step 1), LiCl, Li2S, LiF, TaCl5, and ZrCl4 are prepared according to the general formula Li 1.5 Ta 0.5 Zr 0.5 S 0.25 Cl 5.45 F 0.05 The ingredients were mixed and ball-milled to prepare the first electrolyte layer material, Li. 1.5 Ta 0.5 Zr 0.5 S 0.25 Cl 5.45 F 0.05 The sulfide electrolyte Li6PS5Cl in the secondary coating 0.85 F 0.15 Replace with Li 5.5 PS 4.5 Cl 1.45 F 0.05 .

[0173] The solid-state battery in Example 4 is prepared using the same method as in Example 1, the main difference being that in step 1), LiCl, Li₂S, LiF, NbCl₅, and ZrCl₄ are prepared according to the general formula Li 1.5 Nb 0.5 Zr 0.5 S 0.25 Cl 5.45 F 0.05 The ingredients were mixed and ball-milled to prepare the first electrolyte layer material, Li. 1.5 Nb 0.5 Zr 0.5 S 0.25 Cl 5.45 F 0.05 The sulfide electrolyte Li6PS5Cl in the secondary coating 0.85 F 0.15 Replace with Li 5.5 PS 4.5 Cl 1.45 F 0.05 .

[0174] The solid-state battery in Example 5 is prepared in the same way as in Example 1, except that in step 1), LiCl, Li2S, LiF, ZrCl4, and YCl3 are prepared according to the general formula Li 1.8 Zr 0.9 Y 0.2 S 0.5 Cl 4.95 F 0.05 The ingredients were mixed and ball-milled to prepare the first electrolyte layer material, Li. 1.8 Zr 0.9 Y 0.2 S 0.5 Cl 4.95 F 0.05 The sulfide electrolyte Li6PS5Cl in the secondary coating 0.85 F 0.15 Replace with Li 5.5 PS 4.5 Cl 1.45 F 0.05 The material of the first electrolyte layer is Li. 1.8 Zr 0.9 Y 0.2 S 0.5 Cl 4.95 F 0.05 The XRD pattern is shown in Figure 9.

[0175] The solid-state battery in Example 6 is prepared in the same way as in Example 1, except that in step 1), LiCl, Li2S, LiF, TaCl5, and ZrCl4 are prepared according to the general formula Li 1.5 Ta 0.5 Zr0.5 S 0.5 Cl 4.9 F 0.1 The ingredients were mixed and ball-milled to prepare the first electrolyte layer material, Li. 1.5 Ta 0.5 Zr 0.5 S 0.5 Cl 4.9 F 0.1 .

[0176] The solid-state battery in Example 7 is prepared using the same method as in Example 1, the main difference being that in step 1), LiCl, Li₂S, LiF, TaCl₅, and ZrCl₄ are prepared according to the general formula Li 1.5 Ta 0.5 Zr 0.5 S 0.5 Cl 4.8 F 0.2 The ingredients were mixed and ball-milled to prepare the first electrolyte layer material, Li. 1.5 Ta 0.5 Zr 0.5 S 0.5 Cl 4.8 F 0.2 .

[0177] The solid-state battery in Example 8 is prepared in the same way as in Example 2, except that the thickness of the first electrolyte layer in step 1) is 10 nm.

[0178] The solid-state battery in Example 9 is prepared in the same way as in Example 2, except that the thickness of the first electrolyte layer in step 1) is 80 nm.

[0179] The solid-state battery in Example 10 is prepared using the same method as in Example 1, the main difference being that the sulfide electrolyte Li6PS5Cl in the secondary coating is used instead of the sulfide electrolyte Li6PS5Cl. 0.85 F 0.15 Replace with Li3PS4.

[0180] The solid-state battery in Comparative Example 1 was prepared using the same method as in Example 1, the main difference being that Li2ZrCl6 was used instead of LiTaS as the material for the first electrolyte layer. 0.5 Cl 4.95 F 0.05 .

[0181] The solid-state battery in Comparative Example 2 was prepared using the same method as in Example 1, the main difference being that LiTaS was used. 0.5 Cl5 replaces the first electrolyte layer with LiTaS 0.5 Cl 4.95 F 0.05Specifically, in step 1), LiCl, Li₂S, and TaCl₅ are mixed according to the general formula LiTaS. 0.5 Cl5 was used to mix and ball-mill the ingredients to prepare the oxide electrolyte membrane LiTaS. 0.5 Cl5.

[0182] The solid-state battery in Comparative Example 3 was prepared using the same method as in Example 1, the main difference being that LiTaCl was used. 5.9 F 0.1 LiTaS, the material that replaces the first electrolyte layer 0.5 Cl 4.95 F 0.05 Specifically, in step 1), LiCl, LiF, and TaCl5 are mixed according to the general formula LiTaCl 5.9 F 0.1 The ingredients were mixed and ball-milled to prepare the oxide electrolyte membrane LiTaCl. 5.9 F 0.1 .

[0183] The main parameters of the examples and comparative examples are summarized in Table 1 below:

[0184] Table 1

[0185] Test example:

[0186] (1) Detection of interfacial impedance amplification between the material of the first electrolyte layer and the sulfide solid electrolyte Li6PS5Cl

[0187] Test method: The material of the first electrolyte layer was mixed with the sulfide solid electrolyte Li6PS5Cl, and the impedance increase was measured after standing for 80 hours at 25℃ and 70℃ respectively, compared with the increase at 0 hours.

[0188] The test results are shown in Table 2 below:

[0189] Table 2

[0190] (2) Cyclic stability test of solid-state batteries

[0191] Test method: At 25℃, the solid-state battery cell is first charged to 4.3V (vs. Li+ / Li) at a current density of 0.1C. The charging capacity at this time is recorded as the battery's first charge specific capacity. After resting for 10 minutes, it is discharged to 2.6V (vs. Li+ / Li) at a current density of 0.1C. The discharge capacity at this time is recorded as the battery's first discharge specific capacity.

[0192] First-cycle coulombic efficiency (%) = First-cycle discharge specific capacity / First-cycle charge specific capacity × 100%.

[0193] The test results are shown in Table 3 below.

[0194] Table 3

[0195] (4) Rate performance test of solid-state batteries

[0196] Test method: At 25℃, the solid-state battery cell was first charged to 4.3V (vs. Li+ / Li) at a current density of 0.1C, left to stand for 10 minutes, and then discharged to 2.6V (vs. Li+ / Li) at a current density of 0.1C, and cycled 3 times; then it was cycled 5 times each at charge and discharge rates of 0.33C, 0.5C, 1C, and 2C.

[0197] The test results are shown in Table 4 below.

[0198] Table 4

[0199] As can be seen from the comparison of the embodiments and comparative examples, this application can effectively improve the cycle performance and rate performance of solid-state batteries by setting a specific compound as the first electrolyte layer between the second electrolyte layer of the sulfide electrolyte and the positive electrode active material.

[0200] In addition, properly controlling the thickness of the first and second electrolyte layers can further improve the cycle performance and rate performance of solid-state batteries; using a suitable type of material for the second electrolyte layer in combination with the first electrolyte layer can achieve even better cycle performance and rate performance.

[0201] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0202] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A solid-state battery, comprising a positive electrode material, the positive electrode material comprising a positive electrode active material, a first electrolyte layer coated on the surface of the positive electrode active material, and a second electrolyte layer coated on the surface of the first electrolyte layer; The material of the first electrolyte layer includes Li 1+x1+2z1 A y1 B z1 S a1 Cl 6-2a1-b1 F b1 For compounds, 0 < a1 ≤ 0.5, 0.05 ≤ b1 ≤ 0.2, 0 ≤ y1 ≤ 1, 0 ≤ z1 ≤ 1, where, A and B are heterovalent metallic elements, y1 and z1 are not both 0, the oxidation state of A is V1, the oxidation state of B is V2, x1 = 5 - 2z1 - V1*y1 - V2*z1, 0 ≤ x1 ≤ 1; The material of the second electrolyte layer includes the first sulfide electrolyte.

2. The solid-state battery according to claim 1, wherein, It has one or two of the following characteristics: (1)0.25≤a1≤0.5； (2)0.05≤b1≤0.1。 3. The solid-state battery according to claim 1 or 2, wherein, In the general formula, 1≤V1-V2≤2.

4. The solid-state battery according to any one of claims 1 to 3, wherein, A includes one or more of the elements Ta, Nb, V, Ti, Zr, and Hf; optionally, A includes one or more of the elements Ta and Nb.

5. The solid-state battery according to any one of claims 1 to 4, wherein, z1 is 0 or B includes one or more of the following elements: Zr, Hf, Y, Sc, La, Ce, Eu, Gd, Er, Yb, Ho, In, Al, Fe, Cu, and Sn; optionally, B includes the absence of Zr or Zr.

6. The solid-state battery according to any one of claims 1 to 5, wherein, The material of the first electrolyte layer includes LiTaS 0.5 Cl 4.95 F 0.05 、Li 1.5 Ta 0.5 Zr 0.5 S 0.5 Cl 4.95 F 0.05 、Li 1.5 Ta 0.5 Zr 0.5 S 0.25 Cl 5.45 F 0.05 、Li 2.2 Zr 0.8 Y 0.2 S 0.5 Cl 4.95 F 0.05 、Li 1.5 [[ID=第44]]Ta 0.5 Zr 0.5 S 0.5 Cl 4.9 F 0.1 、Li<* 1.5 Ta 0.5 Zr 0.5 S 0.5 Cl 4.8 F 0.2 、Li 1.2 Ta 0.8 Zr 0.2 S 0.25 Cl 5.45 F 0.05 、Li 1.8 Ta 0.2 Zr[[ID=8*]] 0.8 S 0.25 Cl 5.45 F 0.05 、Li 1.8 Ta 0.2 Zr 0.8 S 0.5 Cl 4.95 F 0.05 、Li 1.9 Ta 0.1 Zr 0.9 S 0.25 Cl 5.45 F 0.05 、Li 1.5 Nb 0.5 Zr 0.5 S 0.25 Cl 5.45 F 0.05 、Li 2.8 Zr 0.8 Y 0.2 S Note: There seem to be some inconsistent or incorrect tags in the original text (e.g., "第44", "8*" which might be errors). The translation is done as accurately as possible based on the provided text. 0.5 Cl 4.95 F 0.05 Li 2.5 Zr 0.5 Y 0.5 S 0.25 Cl 5.45 F 0.05 Li 2.5 Zr 0.5 Yb 0.5 S 0.25 Cl 5.45 F 0.05 and Li 2.5 Zr 0.8 Er 0.2 S 0.25 Cl 5.45 F 0.05 One or more of them.

7. The solid-state battery according to any one of claims 1 to 6, wherein, The first sulfide electrolyte has the following general formula: Li x2 PS y2 Cl z2 F a2 , 0<x2<7, 0<y2≤5.5, 0≤z2≤2, 0≤a2<0.2; Alternatively, 0 < z2 ≤ 2.

8. The solid-state battery according to any one of claims 1 to 7, wherein, The first sulfide electrolyte includes Li6PS5Cl and Li6PS5Cl. 0.85 F 0.15 Li 5.5 PS 4.5 Cl 1.5 Li 5.7 PS 4.7 Cl 1.3 Li 6.2 PS 5.2 Cl 0.8 Li 6.4 PS 5.4 Cl 0.6 Li 5.5 PS 4.5 Cl 1.45 F 0.05 Li 5.5 PS 4.5 Cl 1.35 F 0.15 and Li 5.7 PS 4.7 Cl 1.25 F 0.05 One or more of them.

9. The solid-state battery according to any one of claims 1 to 8, wherein, The positive electrode active material has one or more of the following characteristics: (1) The thickness of the first electrolyte layer is 10 nm to 80 nm; (2) The thickness of the second electrolyte layer is 20 nm to 120 nm; (3) The Dv50 of the positive electrode material is 3μm to 5μm; (4) The positive electrode active material is a single crystal material.

10. The solid-state battery according to any one of claims 1 to 8, wherein, It includes a positive electrode, a solid electrolyte layer, and a negative electrode; The positive electrode sheet includes a positive active layer, and the positive active layer includes the positive electrode material; The solid electrolyte layer includes a second sulfide electrolyte.

11. A positive electrode material, comprising a positive electrode active material, a first electrolyte layer coated on the surface of the positive electrode active material, and a second electrolyte layer coated on the surface of the first electrolyte layer; The material of the first electrolyte layer includes Li 1+x1+2z1 A y1 B z1 S a1 Cl 6-2a1-b1 F b1 For compounds, 0 < a1 ≤ 0.5, 0.05 ≤ b1 ≤ 0.2, 0 ≤ y1 ≤ 1, 0 ≤ z1 ≤ 1, where, A and B are heterovalent metallic elements, y1 and z1 are not both 0, the oxidation state of A is V1, the oxidation state of B is V2, x1 = 5 - 2z1 - V1*y1 - V2*z1, 0 ≤ x1 ≤ 1; The material of the second electrolyte layer includes the first sulfide electrolyte.

12. The cathode material according to claim 11, wherein, The cathode material is the cathode material according to any one of claims 2 to 9.

13. An electrical device comprising a solid-state battery according to any one of claims 1 to 10 or a positive electrode material according to any one of claims 11 to 12.

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